1. Field of the Invention
The present invention relates to a computer program product, system, and method for determining whether a short or long message format is used to communicate zone information in a network.
2. Description of the Related Art
A distributed switch includes a plurality of interconnected data forwarders that provide ports to interconnect end device ports, where an end device comprises a host, storage server, etc. In a distributed Fibre Channel Switch, a controlling switch is in communication with one or more Fibre Channel data forwarders (FCDFs) over a Fibre Channel network. In a distributed Fibre Channel over Ethernet (FCoE) switch, the controlling switch is a controlling FCoE forwarder (cFCF) and is in communication with one or more FCoE data forwarders (FDFs) over an Ethernet network. The data forwarders provide Fibre Channel or FCoE connections to end devices in a Fibre Channel or FCoE Fabric. The controlling switch maintains zone information for the network in which the distributed switch operates and updates the zone information of the data forwarders with changes to zone information or state of devices within the zone, such as the allocation and deallocation of N_Port_IDs for end points connected to data forwarders.
Fibre channel technology provides zoning that allows specification of which devices logged into the switch fabric or Storage Area Network (SAN) may communicate with which other devices. In a distributed switch, the controlling switch maintains zoning information for a Virtual Domain of the distributed switch. As end devices log into the distributed switch and are allocated N_Port_IDs belonging to the Virtual Domain, all of the data forwarders in the distributed switch must be informed of the zoning information as it pertains to the devices that are currently logged into the same Virtual Domain. This is done with a series of NPZD (N_Port_ID and Zoning ACL Distribution) requests from the controlling switch to each of the FCDFs in the distributed switch. Each of these requests carries a payload that describes a new N_Port ID allocation/deallocation and a list of all of the other N_Port_IDs currently allocated in the Virtual Domain and the data forwarders having zoning information affected by the allocation/deallocation, each containing a list of the other N_Port_IDs to which access is allowed However, the amount of zoning information in each NPZD message grows as additional end devices log into the data forwarders. The NPZD messages to the data forwarders can grow several factors in size and require numerous frames to transmit the NPZD message.